Plants of the genus Taraxacum, also commonly known as dandelions, are members of the Asteraceae family. These plants are commonly found in temperate zones of the Northern Hemisphere, and species of dandelions include T. officinale, T. erythrospermum, T. albidum, T. japonicum, T. laevigatum, T. erythrospermum and T. californicum. 
Dandelions are tap-rooted biennial or perennial herbaceous plants with an average length of 15 to 30 cm. The leaves are large, light to dark green in color and cluster in a rosette at the base of the plant. The flowering stalks are upstanding and carries a solitary, terminal inflorescence. The florescence ranges from 7 to 15 mm in diameter and is composed of 140 to 400 yellow, ligulate florets. The fruits are conical achenes, brown and crowned by a white, hairy papus, which allows the seeds to be distributed by wind over long distances.
Taraxacum plant roots often contain a variety of compounds including sesquiterpenes, carotenoids, coumarins, flavonoids, phenolic acids, polysaccharides, eudesmanolides, triterpenes, sterols, steroids and others. Specific examples of such compounds include germacranolide, eudesmanolide, guaianolide, taraxacin, phenylpropanoid glycosides, taraxacoside, lactupircin, lutein, violaxanthin, esculin, scopoletin, quercetin, luteolin, rutin, chrysoeriol, caffeic acid, vanillic acid, syringic acid, ferulic acid, chlorogenic acid, chicoric acid, ρ-hydroxyphenylacetic acids, p-hydroxylbenzoic acid, inulin, glucans, mannans, prunasin, 11β, 13-dihydrolactucin, ixerin D, ainslioside taraxinic acid, β-glucopyranosyl, taraxinic acid, glucosyl ester, 11, 13-dihydrotaraxinic acid, 1′-glucoside, lactucopicrin, lactucin, cichorin, tetrahydroridentin B, taraxacolide-O-β-glucopyranoside, prunasin, dihydroconiferin, syringin, dihydrosyringin, taraxasterol, ψ-taraxasterol, homo-taraxasterol, stigmatsterol, cycloartenol, umbelliferone, taraxalisin, α-amyrin, β-amyrin, arnidiol, faradiol, lupeol, taraxol, taraxaserol, 3β-hydroxylup-18-ene-21-one, β-sitosterol, campesterol, lettucenin A, choline, mucilage, pectin, and taraxerol.
Dandelion extracts have been used in the past as for example antioxidants, diuretics, analgesics, anti-coagulants and anticancer agents. The publication “Evaluation of aqueous extracts of Taraxacum officinale on growth and invasion of breast and prostate cancer cells” International Journal of Oncology 32 (2008): 1085-1090 to Sigstedt reports on the anticancer activity of crude extracts prepared from the leaves (“DLE”), flowers (“DFE”) or roots (“DRE”) of the dandelion species Taraxacum officinale. The crude dandelion extracts in Sigstedt were prepared by 1) soaking 75 g of dried plant parts in water for 24 hours at room temperature; 2) filtering the resulting mixture to remove particulate matter; and 3) lyophilizing the mixture to obtain a powder. Sigstedt observes that DLE reduced the growth of MCF-7/AZ breast cancer cells, and not that of LNCaP C4-2B prostate cancer cells; and that both DFE and DRE failed to influence cancer cell proliferation.
The publication “Anti-carcinogenic Activity of Taraxacum Plant. I” Biol. Pharm. Bull. 22.6 (1999): 602-605 to Takasaki relates to dandelion root extracts prepared from the species Taraxacum japonicum. Takasaki describes extracting dried roots (600 g) of T. japonicum plant three times with 3 L of methanol for five hours each, and then evaporating the methanol solution to afford 109 g of a methanol extract. Takasaki additionally describes the preparation of a water extract obtained from extracting 60 g of T. japonicum roots with 0.38 L of water for 1 hour, and then lyophilizing the resulting solution. Takasaki describes that the methanol and water extracts inhibited initiation and promotion of two-stage chemical carcinogenesis.
In the separate publication “Anti-carcinogenic Activity of Taraxacum Plant. II” Biol. Pharm. Bull. 22.6 (1999): 606-610, Takasaki describes another dandelion root preparation of T. japonicum obtained from extracting dried roots (6.7 kg) with 40 L of n-hexane three times for 8 hours each to produce a 120.5 g extract.
Dandelion plant parts have been utilized to prepare extracts in various forms including capsules and tinctures. Dandelion roots in particular have been harvested for preparing “dandelion coffee” obtained by steeping dried ground plant root in boiling water. It has been appreciated that such conventional forms of dandelion extracts are ordinarily associated with lower anticancer activities, inducing as low as 10% cell death when introduced to a cancerous or tumor tissue.